Facebook is officially announcing on Thursday that its log-in system, Facebook Connect, is officially open for business for non-Facebook sites.

The social network is making the implementation of Facebook Connect self-service, so anyone who has a site with even a smidgen of community features can hook into the Facebook social universe.

As I wrote earlier, it's hard to say no to this program. Not just because adding the capability to a site to let users "register" with their existing Facebook credentials will boost community involvement, but because what users do on these sites can get reflected back to their activity stream on Facebook. It's free marketing.

CitySearch users can now log in with their Facebook credentials.

Because Facebook Connect is not just a registration system, but also a marketing channel with a built-in audience of 130 million monthly active users (according to Facebook), this program will crush competing registration systems.

One can argue the merits of platforms like OpenID or Google's Friend Connect, but a technical or philosophical discussion--where OpenID adherents especially would be able to score points on Facebook Connect boosters--would be trumped by the real world.

Sites will adopt Facebook Connect for two reasons. First, their users are already actively using it; millions of users have OpenID log-ins and don't even know it. And second, because it's not just a registration system, it's that marketing channel.

Self-interest (on the part of site owners) wins over philosophy. Facebook gets that. That's why it wins.

Comments you leave on a Facebook Connect-using site can get posted your your Facebook profile.

Facebook Senior Platform Manager Dave Morin told me that many beta test sites that have been using Facebook Connect (there are several dozen so far) have been seeing users log in with their Facebook IDs instead of their pre-existing site IDs at about a 2:1 ratio. Facebook Connect gives site managers the option to tie their local registration credentials to Facebook IDs, so users can log in either way.

As of this writing, the biggest site using Facebook Connect is CitySearch, Morin said.

Other global registration systems could eventually play in the Facebook Connect ecosystem. In fact, it may eventually be wise for Facebook to allow alternate sign-on systems--such as OpenID--to get users into the Facebook world. But not now.

Disclosure: CNET and publisher CBS are, or will be, using Facebook Connect on various sites. I was not a part of the team that made the implementation decisions.

About the author

Rafe Needleman reviews mobile apps and products for fun, and picks startups apart when he gets bored. He has evaluated thousands of new companies, most of which have since gone out of business.
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